The CIGS (Copper Indium Gallium Diselenide) thin-film solar cell, owing to its high energy conversion efficiency, high absorption coefficient, and lower cost than the crystalline silicon solar cells, is regarded as a promising competitor among the next-generation photovoltaics.
US publication No. US 2010/0233841 disclosed a CIGS-based solar cell characterized in comprising a first buffer layer formed on the CIGS layer and made of Zn(O, S) and a second buffer layer formed on the first buffer layer and made of ZnO. Both buffer layers are deposited in the same ALD (Atom Layer Deposition) process. The prior art can simplify the process for fabricating thin-film solar cells and reduce the cost thereof.
The microstructures fabricated on thin-film solar cells can reduce reflection of incident light, increase light absorption and therefore improve efficiency of the solar cell. Moreover, the thin-film solar cells with microstructures are able to be fabricated on flexible substrates via roll to roll method of continuous manufacturing to further reduce costs.
However, the current methods for fabricating microstructures, including the photolithography, the RIE (Reactive Ion Etching), the laser etching, and the FIB (Focused Ion Beam), are either expensive or complicated. Therefore, a method able to fabricate microstructures on a CIGS material in a simple way should be a breakthrough contribution to the related industries.